Problem Statement:

Zip two lists of Integers.

If the lists are of unequal length, return None; otherwise return Some of (int*int) list.

Solution:

Following naïve solution recurses over elements of the lists, and creates tuple, as part of the zip operation. If both lists are empty, it returns Some [].

The unequal length case is handled by the pattern outlined in line 8 , which simply returns None. Subsequent return calls of the recursion detect it and simply return None.

Thus, resultant signature of zipTwo is given by:

Output: